templates: persist appliance metadata on install

Appliance fields that describe the appliance (vendor information, default
credentials, installation instructions...) were dropped when installing a
template. Keep them in a new appliance_metadata JSON column on the
templates table, filled by the appliance-to-template conversion for both
registry v1-6 and v8 (version level values override the appliance level
ones). The nested schema allows extra fields so future registry fields
persist without a migration.

gns3server/controller/appliance_to_template.py

@@ -23,6 +23,27 @@ from .controller_error import ControllerError
 log = logging.getLogger(__name__)
 
 
+# appliance fields that describe the appliance (vendor information, default
+# credentials...) and are kept on the template as metadata instead of being
+# dropped at installation time
+_APPLIANCE_METADATA_FIELDS = (
+    "description",
+    "vendor_name",
+    "vendor_url",
+    "vendor_logo_url",
+    "documentation_url",
+    "product_name",
+    "product_url",
+    "status",
+    "availability",
+    "maintainer",
+    "maintainer_email",
+    "installation_instructions",
+    "default_username",
+    "default_password",
+)
+
+
 class ApplianceToTemplate:
     """
     Appliance installation.
@@ -61,6 +82,10 @@ class ApplianceToTemplate:
         if appliance_config.get("netmiko_device_type"):
             new_template["netmiko_device_type"] = appliance_config["netmiko_device_type"]
 
+        appliance_metadata = self._build_appliance_metadata(appliance_config, version)
+        if appliance_metadata:
+            new_template["appliance_metadata"] = appliance_metadata
+
         if new_template.get("symbol") is None:
             if appliance_config["category"] == "guest":
                 if "docker" in appliance_config:
@@ -192,6 +217,10 @@ class ApplianceToTemplate:
         if appliance_config.get("netmiko_device_type"):
             new_template["netmiko_device_type"] = appliance_config["netmiko_device_type"]
 
+        appliance_metadata = self._build_appliance_metadata(appliance_config, version)
+        if appliance_metadata:
+            new_template["appliance_metadata"] = appliance_metadata
+
         if not new_template.get("symbol"):
             # apply a default symbol based on the effective category and template type
             if category_before_remap == "guest":
@@ -221,6 +250,26 @@ class ApplianceToTemplate:
 
         return new_template
 
+    def _build_appliance_metadata(self, appliance_config, version):
+        """
+        Builds the appliance metadata kept on the template: the fields that
+        describe the appliance, with version level values (e.g. credentials
+        specific to the installed version) overriding the appliance level ones.
+        """
+
+        version = version or {}
+        metadata = {}
+        for field in _APPLIANCE_METADATA_FIELDS:
+            value = version.get(field)
+            if value is None:
+                value = appliance_config.get(field)
+            if value is not None:
+                metadata[field] = value
+        appliance_id = appliance_config.get("appliance_id")
+        if appliance_id:
+            metadata["appliance_id"] = str(appliance_id)
+        return metadata or None
+
     def get_template_type(self, appliance_config, version):
         """
         Returns the template type of the settings set used to install the given

gns3server/db/models/templates.py

@@ -36,6 +36,7 @@ class Template(BaseTable):
     builtin = Column(Boolean, default=False)
     usage = Column(String)
     netmiko_device_type = Column(String)
+    appliance_metadata = Column(JSON)
     template_type = Column(String)
     tags = Column(JSON)
     compute_id = Column(String)

gns3server/db_migrations/versions/c7e4a9f1d2b6_add_appliance_metadata_to_templates.py

@@ -0,0 +1,26 @@
+"""add appliance_metadata to templates table
+
+Revision ID: c7e4a9f1d2b6
+Revises: b3c7e2a91d4f
+Create Date: 2026-08-16 12:00:00.000000
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = 'c7e4a9f1d2b6'
+down_revision = 'b3c7e2a91d4f'
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+
+    op.add_column('templates', sa.Column('appliance_metadata', sa.JSON()))
+
+
+def downgrade() -> None:
+
+    op.drop_column('templates', 'appliance_metadata')

gns3server/schemas/controller/templates/__init__.py

@@ -34,6 +34,34 @@ class Category(str, Enum):
     firewall = "firewall"
 
 
+class ApplianceMetadata(BaseModel):
+    """
+    Metadata kept on a template installed from an appliance: vendor
+    information, default credentials and other fields that describe
+    the appliance but are not node properties.
+    """
+
+    model_config = ConfigDict(extra="allow")
+
+    appliance_id: Optional[str] = Field(
+        None, description="ID of the appliance the template was installed from"
+    )
+    description: Optional[str] = None
+    vendor_name: Optional[str] = None
+    vendor_url: Optional[str] = None
+    vendor_logo_url: Optional[str] = None
+    documentation_url: Optional[str] = None
+    product_name: Optional[str] = None
+    product_url: Optional[str] = None
+    status: Optional[str] = None
+    availability: Optional[str] = None
+    maintainer: Optional[str] = None
+    maintainer_email: Optional[str] = None
+    installation_instructions: Optional[str] = None
+    default_username: Optional[str] = None
+    default_password: Optional[str] = None
+
+
 class TemplateBase(BaseModel):
     """
     Common template properties.
@@ -57,6 +85,10 @@ class TemplateBase(BaseModel):
         default_factory=list,
         description="User-defined metadata tags (e.g. 'vendor:cisco' or 'model:7200')"
     )
+    appliance_metadata: Optional[ApplianceMetadata] = Field(
+        None,
+        description="Metadata inherited from the appliance the template was installed from"
+    )
 
 
 class TemplateCreate(TemplateBase):